1. Field of the Invention
The present invention relates generally to an optical storage device, and more particularly to a cartridge loading mechanism for an optical storage device.
2. Description of the Related Art
An optical disk has received attention as a memory medium that becomes a core in the recent rapid development of multimedia, and it is usually accommodated in a cartridge case to be provided as an optical disk cartridge for practical use. The optical disk cartridge is loaded into an optical disk drive to perform reading/writing of data (information) from/to the optical disk by means of an optical pickup (optical head).
A recent optical pickup for an optical disk drive intended to realize size reduction is composed of a fixed optical assembly including a laser diode, a polarization beam splitter for reflecting and transmitting a laser beam, and a photodetector for receiving reflected light from an optical disk, and a movable optical assembly including a carriage and an objective lens mounted on the carriage. The carriage is movable in the radial direction of the optical disk along a pair of rails by means of a voice coil motor.
A write-power laser beam emitted from the laser diode of the fixed optical assembly is first collimated by a collimator lens, next transmitted by the polarization beam splitter, next reflected by a beam raising mirror of the movable optical assembly, and finally focused on the optical disk by the objective lens, thereby writing data onto the optical disk. On the other hand, data reading is performed by directing a read-power laser beam onto the optical disk. Reflected light from the optical disk is first collimated by the objective lens, next reflected by the polarization beam splitter, and finally detected by the photodetector, thereby converting the detected optical signal into an electrical signal.
In a conventional cartridge loading mechanism, a turntable assembly having a spindle motor is mounted on a load plate. The turntable assembly is movable between a raised position where the optical disk in the cartridge inserted into the disk drive is chucked to a turntable and a lowered position where the optical disk is unchucked from the turntable. In such a spindle loading type, the load plate is movable between a first position and a second position according to insertion and ejection of the cartridge with respect to the disk drive. The load plate is normally biased toward the second position by a spring.
When the load plate is moved to the second position, the turntable assembly is moved to the raised position, whereas when the load plate is moved to the first position, the turntable assembly is moved to the lowered position. As another loading type, a cartridge loading type is also known in which a cartridge holder is vertically moved to chuck the optical disk to a turntable fixed in vertical position.
The conventional cartridge loading mechanism has an eject arm for ejecting the cartridge from the disk drive. The eject arm is integrally formed with a timing portion engaging with the load plate in the condition where the cartridge is not inserted in the disk drive. In the condition where the cartridge is not inserted in the disk drive, the timing portion of the eject arm is engaged with the load plate to maintain the load plate in the first position, thereby maintaining the turntable assembly in the lowered position.
When the cartridge is inserted into the disk drive, the eject arm is pushed by the cartridge to pivotally move. When the eject arm is pivotally moved to a given position, the timing portion of the eject arm is disengaged from the load plate, so that the load plate is moved to the second position by the biasing force of the spring. Accordingly, the turntable assembly is lifted, so that a reference pin formed on the turntable assembly comes into engagement with a reference hole of the cartridge, and the turntable chucks a hub of the optical disk. As a result, the optical disk is connected to the turntable and rotated at a high speed by the spindle motor to perform reading/writing of data from/to the optical disk by operating the optical pickup.
In the conventional cartridge loading mechanism as mentioned above, the timing portion for determining the timing of chucking of the optical disk to the turntable is integrated with the eject arm, and the distance between a pivotal center of the eject arm and a point of contact of the eject arm and the cartridge inserted into the disk drive is set considerably longer than the distance between the pivotal center and a point of engagement of the timing portion and the load plate. Accordingly, although the eject arm is designed so that the timing portion is disengaged from the load plate when the cartridge pushes the eject arm to pivotally move it and is inserted to a given position, this given position is not constant and considerably varies.
Thus, there are variations in position of the cartridge inserted into the disk drive at the time of disengaging the timing portion from the load plate. As a result, there is a case that the reference pin of the turntable assembly cannot be engaged with the reference hole of the cartridge, causing defective chucking of the optical disk in loading the cartridge. In the case of the cartridge loading type such that the cartridge holder and the cartridge held therein in the disk drive are vertically movable, the reference pin is provided on a fixed member such as a chassis or a base opposed to the cartridge holder. When the cartridge holder is lowered, the reference hole of the cartridge comes into engagement with the reference pin on the fixed member.
It is therefore an object of the present invention to provide a cartridge loading mechanism which can prevent defective chucking of an optical disk in loading a cartridge having the optical disk.
It is another object of the present invention to provide a reliable optical storage device which can prevent defective chucking of an optical disk.
In accordance with an aspect of the present invention, there is provided a storage device comprising a turntable adapted to engage a storage medium for rotatably supporting the storage medium; a load plate adapted to move from a first position to a second position in concert with insertion of a carrier carrying the storage medium into the storage device for chucking the storage medium to the turntable; and a timing arm having a first arm for engaging the load plate to maintain the load plate in the first position, a second arm adapted to engage the carrier inserted into the storage device, and an operational center for cooperating the first arm and the second arm; the distance between the operational center and a position of engagement of the first arm and the load plate being set greater than or equal to the distance between the operational center and a position of engagement of the second arm and the carrier.
The carrier may be a cartridge in which the storage medium is accommodated or a tray for placing the storage medium thereon. The storage medium is selected from any one of a read-only type optical disk, a phase-change type optical disk, a magneto-optical disk, and a magnetic disk. Preferably, the first arm is pivotally movable between a third position for maintaining the load plate in the first position and a fourth position for disengaging the load plate in concert with the insertion of the carrier to allow movement of the load plate to the second position.
Preferably, the storage device further comprises a holder for holding the carrier inserted in the storage device, an eject arm adapted to engage the carrier, and a biasing member for biasing the eject arm in a direction of ejecting the carrier from the storage device. When the storage medium is unchucked from the turntable, the eject arm ejects the carrier from the storage device. The storage device further comprises a base, and a pinion unit rotatably mounted on the base. The eject arm has a rack meshing with the pinion unit.
Preferably, the turntable is mounted on a turntable assembly movable between a raised position where the storage medium is chucked to the turntable and a lowered position where the storage medium is unchucked from the turntable. The carrier has a reference hole, and the turntable assembly has a reference pin adapted to be inserted into the reference hole of the carrier in the raised position.
According to the present invention, the position of the carrier inserted into the disk drive at the time of disengaging the timing arm from the load plate can be made always constant, so that the reference pin of the turntable assembly can be reliably engaged into the reference hole of the carrier, and the turntable can reliably chuck the hub of an optical disk as the storage medium.
The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention.